A patient with pollakiuria micturates more frequently than a healthy person and therefore, pollakiuria causes the patient much trouble in his life. Since micturition is caused by reflective contraction of urinary bladder, a drug which inhibits the reflective contraction is useful for treatment of pollakiuria. Drugs such as Flavoxate hydrochloride [chemical name: 3-methyl-4-oxo-2-phenyl-4H-1-benzopyran-8-carboxylic acid 2-piperidinoethyl ester.hydrochloride] and Oxybutynin hydrochloride [chemical name: .alpha.-cyclohexyl-.alpha.-hydroxy-benzeneacetic acid 4-(diethylamino)-2-butynyl ester.hydrochloride] have been known as drugs for prophylaxis and treatment of pollakiuria based on the above-identified activity (The MERCK INDEX tenth edition, page 587 and 997). On the other hand, Japanese Patent Publication (unexamined) No. 17455 of 1977 and U.S. Pat. No. 4,091,115 disclose 6,7,8,9-tetrahydro-5-phenyl-7-methylamino-5H-benzocyclohepten-5-ol and its 7-dimethylamino compound as intermediate compounds of antidepressant agent. However, any pharmaceutical activity of said compounds has not been known.